As Christmas edges closer, the media is rife with seasonal health stories. But can our Christmas trees really make us sick?

Christmas tree allergyShare on Pinterest
What is Christmas tree syndrome?

Constantly on the lookout for interesting health stories, I stumbled across a collection of articles about Christmas tree syndrome recently, which piqued my interest.

According to a plethora of news outlets and articles spanning the past decade, Christmas trees are a ready source of mold, which can wreak havoc in our respiratory tract and potentially spoil our holiday fun.

This may be an issue for the roughly 13 percent of the population of the United States who are affected by mold allergy. But the studies cited are far from extensive, and mold allergy is not terribly well understood.

So, do you need to be throwing doubtful glances at your carefully decorated Christmas conifer, or is the whole thing a holiday hype?

According to the Asthma and Allergy Foundation of America (AAFA), “[I]f you have an allergy that occurs over several seasons, you may be allergic to the spores of molds or other fungi.”

Spores come in a variety of shapes and sizes, and they are ever-present in our environment — both indoors and outdoors. There may be in excess of 1 million fungal species that inhabit our planet, of which just over 100 families, or genera, can cause mold allergy.

The main culprits, however, are just four: Alternaria, Cladosporium, Penicillium, and Aspergillus.

Mold spores become dangerous when they reach critical levels. This is the case for individuals who have a mold allergy, as well as those with other allergies or asthma, where mold exposure can serve as a secondary trigger and make symptoms worse.

Our weather and light levels affect the composition and levels of individual spore species, which are in constant flux. Our knowledge of critical spore levels is far from extensive, but studies have suggested that for Alternaria, levels can be as low as 100 spores per cubic meter, while for Cladosporium, it is 3,000 spores per cubic meter.

But what does this have to do with our Christmas trees?

It all started in 1970, when Dr. Derek M. Wyse published a paper titled “Christmas tree allergy: mold and pollen studies” in the Canadian Medical Association Journal.

He found that approximately 7 percent of allergic people saw a spike in symptoms when they had a Christmas tree in their home.

Yet, when he measured the variety of mold spores in 10 festive homes, he found his results largely inconclusive because the type of mold he found in the homes varied. Nonetheless, the term Christmas tree allergy was coined.

Fast forward to 2007, when Dr. Phillip Hemmers reported at the annual meeting of the American College of Allergy, Asthma & Immunology in Dallas, TX, that he had followed the fate of one particular Christmas tree.

He found that mold spores had gone up by more than fivefold during a 14-day period over the holidays, reaching 5,000 spores per cubic meter at the end of the festive period.

In 2011, Dr. Lawrence E. Kurlandsky — along with his colleagues from the State University of New York Upstate Medical University in Syracuse — published a more extensive study.

Having analyzed clippings from 28 Christmas trees belonging to their team and fellow staff, they found 53 mold species, of which 70 percent were potentially harmful.

Does that mean the end for the Medical News Today editorial office Christmas tree?

Winter sees an annual peak in colds, flu outbreaks, and asthma attacks. The exact reasons aren’t known. But whether your Christmas tree or a combination of other factors is really to blame is difficult to say.

However, if you do have allergies or asthma, it’s worth taking the potential spike in tree-related spore levels seriously. Dr. Kurlandsky recommends washing your tree before bringing it inside, keeping it only for the minimum time possible, and using an air purifier to keep spore levels in check.

The AAFA recommend keeping your living spaces clear of other sources of mold and reducing damp by lowering humidity levels.

For those not affected by allergies, however, the alarm bells are off. “If you and your children don’t have any obvious allergies, then it is probably not going to bother you,” Dr. Kurlandsky says.

For now, our office Christmas tree is safe after all.